Valves and, particularly, plug valves are employed in a wide variety of applications, such as, industrial, residential, commercial, petrochemical, automotive and the like for regulating the flow of fluids. Often, it is critical that accidental or malicious tampering of the valves be prevented. Controlling and/or preventing inadvertent accidents or mistakes can particularly be of significant importance in areas utilizing a large number of valves or when the fluids controlled by such valves are hazardous. Since the inadvertent or mistaken opening or closing of the valves may result in economic or possibly even personal injury, it is often desirable to restrict access to the valves and particularly, restrict access to the valve stem(s) by way of which those valves can be regulated in open and closed positions. Frequently, access to the valve stem can be prevented by utilizing a locking mechanism, which locks the valve in a predetermined position and additionally prevents undesirable tampering of the valve.
A variety of such locking mechanisms have been proposed in the past. Although adequate in most regards, such valves are nevertheless lacking in at least some aspects. For example, in at least some conventional locking mechanisms, the handle or lever utilized for operating the valve is removed and placed into a pocket, which is locked. Such locking mechanisms do not necessarily lock the valve itself, which is still subject to tampering or accidental operation by utilizing other handles or handle-like mechanisms. Some other conventional locking mechanisms are equipped with structures that are capable of being secured to the handle while being connected to the valve. Such mechanisms although effective in preventing accidental (or malicious) operation of valves having handles, these mechanisms are generally not effective in valves that do not have handles or otherwise valves in which such handles are removed after operation. Some further conventional locking mechanisms require complex tools and/or specialized skills to operate. Some additional locking mechanisms are described in U.S. Pat. Nos. 5,238,141, 5,244,008, 5,638,858 and 5,927,313.
In view of foregoing, it would be advantageous if an improved locking mechanism for restricting accidental or malicious tampering of the valve is provided. It would additionally be advantageous if such a locking mechanism is capable of operating in valves with removed handles. It would further be advantageous if the locking mechanism were easy to handle and operate without requiring any unnecessary tools or specialized skills.